MAG4Health脑磁图仪 4He-OPM脑磁图


简介 MAG4Health是一个完全集成的氦原子 4He OPM MEG系统,基于专有的量子技术,实现新一代的MEG研究。
品牌 MAG4Health
型号4He-OPM-MEG


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MAG4Health新型脑磁图仪4He-OPM-MEG由BrainBox公司面向全球推广销售,脑盒科技 (BrainBox China)为大中华区总代理,敬请致电400-880-8790了解更多产品详情。


MAG4Health 4He OPM-MEG System

MAG4Health脑磁图仪是一个全新的完全集成的氦原子光泵磁强计(4He OPM)-MEG系统,基于专有的量子技术,实现了新一代的神经成像和MEG,有48个传感器的全头覆盖系统。


What is MEG?

脑磁图(MEG)是一种用于实时成像脑功能的无创技术。该方法是基于测量(主要)由同步树突电流通过神经元组件在颅外产生的磁场。这些领域的数学模型允许开发三维图像(称为源定位),描述大脑对不同的实验环境或认知要求作出反应时电活动的瞬间变化。


What is OPM-MEG?

近年来,在脑磁图仪MEG领域出现了一种新的磁场感应方法。OPM是磁场传感器,其灵敏度与SQUID相当,不需要低温冷却。这导致了新型MEG系统的发展,'OPM-MEG'脑磁图仪在数据质量、覆盖均匀性、运动稳健性和系统复杂性方面开始超过现有的技术水平,而这是一种相对较新的技术。

许多这些障碍正开始被下一代的脑磁图仪MEG技术所消除。"OPM-MEG "有可能通过利用被称为光学泵磁强计(OPM)的量子传感器,大幅超越现有技术水平。这可能导致数据质量的提高(更高的灵敏度和空间分辨率),适应任何大小或形状(从婴儿到成人)的头颅,运动弹性(参与者可以在扫描过程中自由移动),以及一个不太复杂的成像平台(不依赖低温技术)。


与传统的MEG脑磁图仪相比,光泵磁强计(OPM)脑磁图仪具有各种优势,包括:

1. 增加信号灵敏度

2. 提高空间分辨率

3. 更大的覆盖均匀性

4. 符合寿命要求

5. 在扫描过程中,参与者可以自由移动

6. 操作成本低,不需要过冷处理

7. 降低系统的复杂性

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What are the applications for OPM-MEG?

OPM-MEG脑磁图仪可用于测量一些通常由MEG和EEG报告的电生理事件。通常,对许多模式的感觉刺激的诱发反应进行评估,OPM可以提供高保真的测量(Borna A.et al. Non-invasive functional-brain-imaging with an OPM-based magnetoencephalography system. PLoS One. 2020; 15e0227684)

同样,在许多频段上都能检测到脑震荡,并具有良好的信噪比(Iivanainen J.et al. Potential of on-scalp MEG: robust detection of human visual gamma-band responses. Hum. Brain Mapp. 2019; 41: 150-161). 使用可穿戴的OPM-MEG传感器,癫痫活动可以被记录,表明未来临床应用的潜力(Feys, Odile et al. “On-Scalp Optically Pumped Magnetometers versus Cryogenic Magnetoencephalography for Diagnostic Evaluation of Epilepsy in School-aged Children.” Radiology vol. 304,2 (2022): 429-434)

OPM-MEG脑磁图仪与其他功能神经成像技术相比具有的优势:例如,fMRI**于血流动力学测量,时间分辨率差,要求参与者在一个封闭嘈杂的区域,并要求参与者保持不动,因此很难在自然环境下量化大脑活动。虽然EEG和fNIRS在扫描时能提供真实的活动,但它们的空间(EEG)或时间(fNIRS)分辨率有限(fNIRS)。由于这些原因,在功能成像领域,OPM-MEG脑磁图仪开始作为一种新兴的工具脱颖而出,在许多方面超过了目前的技术。


有许多应用领域可以从这些优势中受益,例如:

  • 更高的空间精确度和灵敏度将对所有功能图谱研究极为有利,包括临床应用(如绘制癫痫样活动图)和基础研究。使用OPM-MEG脑磁图仪比使用SQUID MEG更容易扫描新生儿、婴儿和儿童,这为临床和基础研究提供了前景(e.g., the study of neurodevelopmental problems) (e.g., examining how electrophysiological activity and connectivity change during the early years of life)。

  • 能够在自由移动时进行扫描的功能使那些难以忍受传统扫描仪的人,如有行动障碍的人,可以使用脑磁图仪MEG。此外,运动耐受性为新形式的探索提供了机会(e.g., immersive environments, or naturalistic scenarios)。

  • OPMs并不局限于对大脑的研究;它们也被用来评估周围神经系统、肌肉、心脏、甚至肠道神经系统的电生理学。


MAG4Health 4He OPM MEG系统特点


无须低温或额外加热

MAG4Health OPM MEG系统在室温下运行,与低温MEG系统相反,它既不需要液氮冷却,也不需对气室额外加热。


模块化设计

MAG4Health的电子设备依赖于模块化方法,允许在传感器之间及刺激设备之间保持精确同步的前提下支持升级传感器数量,提供简单易用的数字化数据采集和用户友好的计算机界面。


自补偿传感器

MAG4Health OPM MEG系统提供了一个闭环系统,具有大动态范围(高达250 nT),零交叉轴效应和稳定的转换功能


舒适,可移动设计

通过在室温下操作及允许头部移动,MAG4Health OPM MEG系统可以避免引起被试身体不舒适或受到发热困扰。


长寿命

4He OPM相对于碱金属OPM传感器具有更长的使用寿命,使用寿命长达10年以上,可以有效提高整体使用寿命和使用成本。

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核心技术参数



带宽

Bandwidth (Hz)


DC-2,000Hz

To allow the recording of a wider range of brain dynamics, including   epileptic activity such as HFO and fast ripple.   允许记录更广泛的大脑动态变化,包括癫痫活动,如HFO和Fast ripple。

动态范围

Dynamic Range (nT)

up to 300nT

Resulting in reduced requirements in magnetic shielding and improvements in susceptibility to background magnetic noise (reduced sensor saturation or   movement-related noise), with no requirement for additional field-nulling coils.   大动态范围降低了对磁屏蔽的要求,改善了对背景磁噪声的敏感性(减少了传感器的饱和度或与运动有关的噪声),而且不需要额外的磁场抵消线圈。

传感器噪声

Sensor Noise (fT/rtHz)

<35ft/rtHz

Lower sensitivity is compensated by the fact that sensors are in direct   contact with the scalp, resulting in higher signal acquisition as a consequence   of the absence of thermal insulation required with other OPM systems.   由于传感器与头皮直接接触,低灵敏度得到补偿,由于没有其他OPM系统所需的热绝缘,导致了较高的信号采集。

功率耗散(50个传感器)

Power Dissipation (50 sensor array) (W)

1W

Allowing   for sensors to operate at room temperature with no issues with the longevity of use caused by thermal heating. This also allows for sensors to be directly   positioned and placed on the subject's scalp which has seen significant   improvements in signal-to-noise ratio.   允许传感器在室温下运行,没有因热加热而引起的使用寿命的问题。这也使得传感器可以直接定位并放置在受试者的头皮上,信噪比有了显著的改善。

精度

Accuracy

Closed Loop on 3 axis

Resulting in

  • No drift of sensors   传感器无漂移

  • Reduced   inconsistency within the network giving a more accurate reconstruction of   brain current (activity)   减少了网络内的不一致性,使大脑电流(活动)的重建更加准确。

  • No Cross Axis   Projection Error (CAPE)   没有跨轴投影误差

  • Improved stability   to magnetic disturbances   提高了对磁干扰的稳定性

传感器定位

Sensor Localisation

Helmet fixation with Auto Localisation

Achieved using a anti-localising scanning method for each   sensor with respect to other sensors and to a head reference frame.   使用反定位扫描方法来实现,每个传感器相对于其他传感器和头部参考框架都是如此。

传感器尺寸

Sensor Dimension (mm)

19 x 19 x 50mm

Allowing for the placement of 96 (adult) and 85 (child) sensors within   the helmet.   允许在头盔内放置96个(成人)和85个(儿童)传感器。

可靠性(寿命)

Reliability (Longevity)

~10year

Following extensive accelerated ageing tests and based on He4 OPM technology that has been developed for use in space applications (tests still ongoing).   经过广泛的加速老化测试,并基于已开发的用于空间应用的He4 OPM技术(测试仍在进行中)。




参考文献


  1. A New Generation of OPM for High Dynamic and Large Bandwidth MEG: The 4He OPMs—First Applications in Healthy Volunteers. Gutteling, Tjerk P., Mathilde Bonnefond, Tommy Clausner, Sébastien Daligault, Rudy Romain, Sergey Mitryukovskiy, William Fourcault, Vincent Josselin, Matthieu Le Prado, Agustin Palacios-Laloy, Etienne Labyt, Julien Jung, and Denis Schwartz. 2023, 23, 2801. March 2023


相关资源



  1. Magnetoencephalography with optically pumped magnetometers (OPM-MEG): the next generation of functional neuroimaging Brookes MJ, Leggett J, Rea M, Hill RM, Holmes N, Boto E, Bowtell R. (2022)


  2. Non-invasive functional-brain-imaging with an OPM-based magnetoencephalography system Borna, A. et al. (2020) “Non-invasive functional-brain-imaging with an OPM-based magnetoencephalography system,” PLOS ONE, 15(1). Available at: https://doi.org/10.1371/journal.pone.0227684.

  3. Potential of on‐scalp meg: Robust detection of Human Visual gamma‐band responses Iivanainen, J., Zetter, R. and Parkkonen, L. (2019) “Potential of on‐scalp meg: Robust detection of Human Visual gamma‐band responses,” Human Brain Mapping, 41(1), pp. 150–161. Available at: https://doi.org/10.1002/hbm.24795.

  4. On-scalp optically pumped magnetometers versus cryogenic magnetoencephalography for diagnostic evaluation of epilepsy in school-aged children Feys, O. et al. (2022) “On-scalp optically pumped magnetometers versus cryogenic magnetoencephalography for diagnostic evaluation of epilepsy in school-aged children,” Radiology, 304(2), pp. 429–434. Available at: https://doi.org/10.1148/radiol.212453.

  5. Magnetocardiography measurements with 4He vector optically pumped magnetometers at room temperature Morales, S., Corsi, M.C., Fourcault, W., Bertrand, F., Cauffet, G., Gobbo, C., Alcouffe, F., Lenouvel, F., Le Prado, M., Berger, F., Vanzetto, G. and Labyt, E. (2017).

  6. Parametric resonance magnetometer based on elliptically polarized light yielding three-axis measurement with isotropic sensitivity Le Gal, G., Rouve, L.-L. and Palacios-Laloy, A. (2021).

  7. Measuring MEG closer to the brain: Performance of on-scalp sensor arrays Iivanainen, J., Stenroos, M. and Parkkonen, L. (2017).

  8. Magnetoencephalography With Optically Pumped 4He Magnetometers at Ambient Temperature Labyt, E., Corsi, M.-C., Fourcault, W., Palacios Laloy, A., Bertrand, F., Lenouvel, F., Cauffet, G., Le Prado, M., Berger, F. and Morales, S. (2019).

  9. Optimal design of on‐scalp electromagnetic sensor arrays for brain source localisation Beltrachini, L., von Ellenrieder, N., Eichardt, R. and Haueisen, J. (2021)

  10. Second-order effects in parametric-resonance magnetometers based on atomic alignment Beato, F. and Palacios-Laloy, A. (2020).

  11. Theory of a He4 parametric-resonance magnetometer based on atomic alignment Beato, F., Belorizky, E., Labyt, E., Le Prado, M. and Palacios-Laloy, A. (2018).

  12. Performance Analysis of Optically Pumped 4He Magnetometers vs. Conventional SQUIDs: From Adult to Infant Head Models Zahran, S., Mahmoudzadeh, M., Wallois, F., Betrouni, N., Derambure, P., Le Prado, M., Palacios-Laloy, A., and Labyt, E. (2022).

  13. Tri-axial Helium-4 Optically Pumped Magnetometers for MEG Palacios-Laloy, A., Le Prado, M., and Labyt, E. (2022).

  14. Helium-4 magnetometers for room-temperature biomedical imaging: Toward collective operation and photon-noise limited sensitivity Fourcault, W., Romain, R., Le Gal, G., Bertrand, F., Josselin, V., Le Prado, M., Labyt, E., and Palacios-Laloy, A. (2021)